用于继承DataTemplate的Setter

Question

我读了this主题。但不明白如何在继承DataTemplate中创建一个Setter。 我的代码：

<DataTemplate x:Key="base">
  <TextBlock Text="{Binding Path=DisplayString}" x:Name="PART_DisplayString"/>
</DataTemplate>

<DataTemplate x:Key="stage">
  <ContentPresenter Content="{Binding}" ContentTemplate="{StaticResource base}">
    <ContentPresenter.Style>
      <Style>
        <Setter TargetName="PART_DisplayString" Property="TextBlock.Text" Value="{Binding Path=DisplayString, StringFormat=Stage {0}}"/>
      </Style>
    </ContentPresenter.Style>
  </ContentPresenter>
</DataTemplate>

<DataTemplate x:Key="room">
  <ContentPresenter Content="{Binding}" ContentTemplate="{StaticResource base}">
    <ContentPresenter.Style>
      <Style>
        <Setter TargetName="PART_DisplayString" Property="TextBlock.Text" Value="{Binding Path=DisplayString, StringFormat=Room {0}}"/>
      </Style>
    </ContentPresenter.Style>
  </ContentPresenter>
</DataTemplate>

我收到错误姓名＆＃34; PART_DisplayString＆＃34;无法识别。